Pulverized-fuel furnace



BERGMANV. PULVERIZED FUEL FURNACE. PPPP ICATION FILED JAN. 7,1920. lg,

2 EEEEEEEEEEEE 1. E.; Z

Laits Haj@- Berman Y Patented July 4;, i922.,

L. Hl BERGMAN.

PULVERIZED FUEL FURNACE.

APPLICATION HLED JANJ, 1920.

1,421,898, Patented .my 4, 1922.

' 2 SHEETS-SHEET 2. q IL E- 2 Lars Hugo Bre rman u rrED STATES Lens HUGO BERGMAN,

PULVERIZED-FUEL FUBNACE.

PATENT OFFICE.

or CHICAGO, ILLINOIS.

Specification `o f Letters Patent. I,

Patented July 4, 1922.

Application led January 7, 1920. Serial No. 350,015.

To all whom it may concern;

Be it known that I,LARs HUGO BERGMAN, a citizen of the United States, and a resident of the city of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in a Pulverized-Fuel Furnace; and I do hereby.v declare that the following is a full, clear, and exact andthe other to supply thel necessary additional oxygen for complete combustion.

Powdered fuel, even when crushed so that 80%will pass 100 mesh, takes an appreciable time to burn so thatprovision must be made y to allow sufficient time for complete combustion.

Not only is it necessary to allow time for combustion, but it is also desirable to provide means for intimately mixing the powdered fuel with the air in which it is burnt.

One of the objects, therefore, of the present invention is to provide means whereby the powdered p fuel and air are caused to travel over a path of sufiicient length to allow of complete combustion of the fuel.

Another object 'of the Yinvention is to provide means for intimately mixing the powdered fuel with the :air in which it is burnt..

A further object of the invention is to provide improved means for collecting the ash produced by the burning of the fuel.

A Other and' further important objects of the invention will be apparent from the disclosures in the drawings and specification.

The invention (in a preferred form) is illustrated in the drawings and hereinafter more fully described.`

On the drawings:

Figure 1 is afront elevation of a furnace and boiler constructed in accordance with the present invention, one-half of the figure being in section on the line 1--1 of Figure 2.

Figure 2 is a section on the line 2-2 of Y, 1

is lsurrounded by Virebrick and thereby lpro- Figure 1. Figure 3 is a section on the'l1ne 3--3 of Figure 2, the nozzles'being` shown 1n eleyation.

Figure 4 is a vertical-section through one of the pulverized fuel in]ectors.

As shown on the drawings The furnaces shown form the fire-boxes of l a series of watertube boilers, each denoted by the reference numeral 1, mounted in brick work 2 in the usual way. The furnace itself conslsts of a` fire-brick chamber 3 having an arched roof 4, a. front wall 5, and a bottom 6, the rearward part 7 o f which slopes upwardly towards the water tubes 8 of the boilers.A Powdered fuel, usually coal dust, is

stored in a series-of hoppers 9 arranged along the frontof the boilers. The lower parts of these hoppers communicate with worm feeding devices 10 adaptedI to supply powdered fuel at a uniform rate to vertical pipes 11 which. carry the fuel to fuel nozzles 12. The necessary air for injection of the powdered fuel and for the combustion thereofl is supplied from a blower or fan (not shown) through a conduit 13 from which lead branch connections 14 to the vrespective fuel nozzles. r

The construction of` each nozzle is shown more particularly in Figure 4 in which it is seen that the nozzle comprises a chamber 15 at its upper end to which air is supplied through one of the pipes 14. From the lower end of this chamber extend curved concentrically arranged pipes 16 and 17. lCentrally arranged in the top of the chamber 15 is the end of the pipe 11 to which is connected by suitable means a conical jet 18, by which powdered lfuel is directed into the inner of the two concentric pipes. The air iiowing from the chamber 15 downwardly through the pipes 16 and 17 is divided into two concentric streams, the outer one being of air only while the inner one consists of air carrying with it particles of coal dust. It will be seen that slow moving currents of air will be sufficient to carry the fuel into the furnace, on account of the peculiar construction and disposition of the-burners.

These nozzles are arranged in the side walls 21 of the lchamber 3 adjacent to its upper edge so as 'to direct streams of air inwardly, downwardly and forwardly as indicatedbythe arrows in the various figures. Adjacent eachI nozzle the side walls are thickened, as at 22, so that the entire nozzle tectedagainst the extreme heat of the furnace. Pairs of nozzles are employed to produce converging and mutually impinglng streams of air with the result that each of the streams is thoroughly brokenup, thereby intimately mixing the air introduced merely for the purposeV of completing combustion with the streams of air which act to propel the pulverized coal' into the furnace. In this way a very satisfactory intermixture of the fuel and the airis obtained. Further, by directing the streams of air downwardly and forwardly the particles of fuel are retained in the chamber 3 sufficiently long eithertoburn completely' therein or to burn to such an4 extent that combustion is completed as the gases pass through the tubes 8 of the boilers. One other result of causing the gases to ow around this circuitous and roughly circular path is to aid in the separation of the ash which is thrown against and collects upon the inclined bottom 7 of the chamber. The ashes may be removed from time to time through doors 20 arranged alongr -the lower edge of the front wall 5. Sight holes 19 may also be provided in this front wall so that the operation of the furnace may be observed.

I am aware thatvmany changes may be made andnumerous details of constructions may be varied through a'wide range without departing from the principles of this invention, and I therefore do not purpose limiting the patent granted hereon` otherwise than necessitated by the prior art.

I claim asmy invention:

l; In a furnace for pulverized fuel, a combustion chamber. downwardly directed fuel conduits, air chambers one surrounding the mouthof each fuel conduit, mixture conduitsleadingfrom each of said air chambers into the combustion chamber, said mixture conbustion chamber, downwardly directed fuel conduits,- air chambers onesurrounding the mouth of'each fuel conduit, mixture conduits leading from each of saidair chambers into the combustion chamber, said mixture conduits being `curved so as to deliver streams inclined downward and toward the front of the combustion chamber, said inclined streams converging toward the front of the combustion chamber, air conduits surrounding each of said mixture conduits respectively, whereby the streams deliveredeach consist, at the point of delivery, of a central stream of mixture 'of airand fuell and an annular. surrounding stream of air relatively free from fuel, lan outlet at therear of s aid combustion chamber, means for con-` veying pulver1zed fuel to said fuel-conduits,

and means for conveying airvunder pressure to said air chambers.

In testimony whereof I have hereunto 

